Liquid-activated formulation with hot melt binding matrix

ABSTRACT

A liquid-activated formulation is provided, comprising a liquid-activated colorant, a hydrochromic ionic compound, an opacifier, and a hot melt binding matrix.

FIELD OF INVENTION

Disclosed are liquid-activated formulations in a hot melt bindingmatrix, for use as wetness/fluid indicators in absorbent articles.

BACKGROUND OF THE INVENTION

Many disposable absorbent articles comprise a wetness indicator. Wetnessindicator compositions may comprise a colorant adapted to change inappearance, i.e., appear, disappear, change color, etc., upon contactwith liquids such as urine, runny bowel movements, menses, etc., in thearticle. The color changing active used in many wetness indicatorcompositions are pH indicators such as bromocresol green or the like,which changes color from yellow to blue in the pH range of 3.8 to 5.4.Upon contact with a liquid, such as urine, the pH indicator will changecolors to indicate the presence of the liquid, due to the higher pH ofthe urine.

However, current pH-based wetness indicators may be unreliable, havingissues such as premature triggering and/or leaching, plus there arelimits as to the variety of color options available. Therefore, there isa continuing need for simple wetness/fluid indicators that can provide avariety of color options. There is also a continuing need for ways toincorporate such wetness/fluid indicators into absorbent articles.

SUMMARY OF THE INVENTION

A liquid-activated formulation is provided, comprising aliquid-activated colorant, a hydrochromic ionic compound, an opacifier,and a hot melt binding matrix.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of an absorbent article according to an aspect ofthe invention.

FIG. 2 is a front view of an absorbent article according to an aspect ofthe invention.

FIG. 3 is a cross section of an absorbent article of FIG. 1 according toan aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Absorbent article” refers to devices which absorb and contain bodyexudates and, more specifically, refers to devices which are placedagainst or in proximity to the body of the wearer to absorb and containthe various exudates discharged from the body. Absorbent articles mayinclude diapers, training pants, adult incontinence undergarments,feminine hygiene products, breast pads, care mats, bibs, wound dressingproducts, and the like. As used herein, the term “body fluids” or “bodyexudates” includes, but is not limited to, urine, blood, vaginaldischarges, breast milk, sweat and fecal matter.

“Absorbent core” means a structure typically disposed between a topsheetand backsheet of an absorbent article for absorbing and containingliquid received by the absorbent article and may comprise one or moresubstrates, absorbent polymer material disposed on the one or moresubstrates, and a thermoplastic composition on the absorbent particulatepolymer material and at least a portion of the one or more substratesfor immobilizing the absorbent particulate polymer material on the oneor more substrates.

“Absorbent polymer material,” “absorbent gelling material,” “AGM,”“superabsorbent,” and “superabsorbent material” are used hereininterchangeably and refer to cross linked polymeric materials that canabsorb at least 5 times their weight of an aqueous 0.9% saline solutionas measured using the Centrifuge Retention Capacity test (Edana441.2-01).

“Comprise,” “comprising,” and “comprises” are open ended terms, eachspecifies the presence of what follows, e.g., a component, but does notpreclude the presence of other features, e.g., elements, steps,components known in the art, or disclosed herein.

“Consisting essentially of” is used herein to limit the scope of subjectmatter, such as that in a claim, to the specified materials or steps andthose that do not materially affect the basic and novel characteristicsof the subject matter.

“Diaper” refers to an absorbent article generally worn by infants andincontinent persons about the lower torso so as to encircle the waistand legs of the wearer and that is specifically adapted to receive andcontain urinary and fecal waste. As used herein, term “diaper” alsoincludes “pants” which is defined below.

“Fiber” and “filament” are used interchangeably.

A “nonwoven” is a manufactured sheet, web, or batt of directionally orrandomly orientated fibers, bonded by friction, and/or cohesion and/oradhesion, excluding paper and products which are woven, knitted, tufted,stitch-bonded incorporating binding yarns or filaments, or felted bywet-milling, whether or not additionally needled. The fibers may be ofnatural or man-made origin and may be staple or continuous filaments orbe formed in situ. Commercially available fibers have diameters rangingfrom less than about 0.001 mm to more than about 0.2 mm and they come inseveral different forms: short fibers (known as staple, or chopped),continuous single fibers (filaments or monofilaments), untwisted bundlesof continuous filaments (tow), and twisted bundles of continuousfilaments (yarn). Nonwoven fabrics can be formed by many processes suchas meltblowing, spunbonding, solvent spinning, electrospinning, andcarding. The basis weight of nonwoven fabrics is usually expressed ingrams per square meter (gsm).

“Pant” or “training pant”, as used herein, refer to disposable garmentshaving a waist opening and leg openings designed for infant or adultwearers. A pant may be placed in position on the wearer by inserting thewearer's legs into the leg openings and sliding the pant into positionabout a wearer's lower torso. A pant may be preformed by any suitabletechnique including, but not limited to, joining together portions ofthe article using refastenable and/or non-refastenable bonds (e.g.,seam, weld, adhesive, cohesive bond, fastener, etc.). A pant may bepreformed anywhere along the circumference of the article (e.g., sidefastened, front waist fastened). While the terms “pant” or “pants” areused herein, pants are also commonly referred to as “closed diapers,”“prefastened diapers,” “pull-on diapers,” “training pants,” and“diaper-pants.” Suitable pants are disclosed in U.S. Pat. No. 5,246,433,issued to Hasse, et al. on Sep. 21, 1993; U.S. Pat. No. 5,569,234,issued to Buell et al. on Oct. 29, 1996; U.S. Pat. No. 6,120,487, issuedto Ashton on Sep. 19, 2000; U.S. Pat. No. 6,120,489, issued to Johnsonet al. on Sep. 19, 2000; U.S. Pat. No. 4,940,464, issued to Van Gompelet al. on Jul. 10, 1990; U.S. Pat. No. 5,092,861, issued to Nomura etal. on Mar. 3, 1992; U.S. Patent Publication No. 2003/0233082 A1,entitled “Highly Flexible And Low Deformation Fastening Device”, filedon Jun. 13, 2002; U.S. Pat. No. 5,897,545, issued to Kline et al. onApr. 27, 1999; U.S. Pat. No. 5,957,908, issued to Kline et al on Sep.28, 1999; and U.S. Ser. No. 11/197,197 to LaVon et al filed Aug. 4,2005; Ser. No. 11/224,462 to Lavon et al filed on Sep. 12, 2005; Ser.No. 11/286,614 to LaVon on Nov. 23, 2005; Ser. No. 11/286,612 to LaVonon Nov. 23, 2005; and Ser. No. 11/709,500 issued to LaVon et al on Feb.27, 2007.

“Substantially surfactant free” is used herein to describe an articlecomponent, such as a dusting layer, that contains less than 10% byweight of a surfactant or mixture thereof, less than 5% by weight ofsurfactant, less than 1% by weight of surfactant, no surfactant, or nomore than an immaterial amount of surfactant where the surfactant may beanionic, cationic, nonionic, amphoteric or may include mixtures thereofand function to increase the wettability of the article component byreducing the contact angle of synthetic urine (as disclosed in U.S. Pat.No. 6,772,708 to Klofta) in contact with the surface of the articlecomponent (e.g., fibers of a nonwoven material or the surface of afilm).

Binding Agents

A binding agent may be any material which immobilizes a liquid-activatedcolorant, or combination of colorants, within the matrix to hinderleaching of the colorant(s) into a diaper core or other regions of anabsorbent article. To optimize the contrast and vibrancy of the colors,it is much preferred to “lock” the colorant within the matrix before andafter contact with a fluid like urine. The binding agents can not onlyhinder the leaching of the color outside of the matrix, but also aid inbinding the entire liquid-activated formulation to a component of theabsorbent article. For example, the binder can aid in forming a strongbond between the surface of the diaper backsheet and theliquid-activated formulation. There are various materials which may besuitable for use as a binding agent in a hot melt binding matrix for theliquid-activated formulations of the present invention.

In one embodiment, possible binding agents include, but are not limitedto, rosins, rosin esters, polymerized rosins, pentaerythritol rosinesters, modified styrene-acrylic polymers and their salts, styrenatedterpenes, polyterpene resins, terpene phenolics, and combinationsthereof. Also suitable as binders are adhesives, quaternary ammoniumcompounds, quaternary polymers, rubbers, latexes and latex emulsions,waxes, surfactants, polyethylene glycols, polyvinyl alcohols, andcombinations thereof.

A suitable rosin mixture may be the combination of Arizona Chemical'sSylvatac RE98 and Eastman's Poly-Pale™. The Sylvatac RE-98 is apentaerythritol rosin ester and the Sylvaros PR-295 is a polymerizedrosin. Both are economical matrix ingredients, both can contribute to adarker color in the dry state, both aid in maintaining effectivecohesive and adhesive forces, and their acidic nature helps preserve thecolorant in its dry state color. In addition to being a suitable bindingagent, rosin esters, polymerized rosins, and pentaerythritol rosinesters may also be effective solubilizers for some of the otheringredients in these formulations. Furthermore, while not wishing to belimited by theory and as noted, the acidity of some rosin esters,polymerized rosins and pentaerythritol rosin esters is believed tocontribute to the stabilization of particular dyes, such as, but notlimited to, pH indicators. For example, some of these rosins containacidic carboxylate groups which aid in keeping a colorant likebromocresol green (free acid) in its acidic yellow state. When using thefree acid form of bromocresol green, this acidic yellow state is thepreferred color for the dry state of the wetness indicator compositionbefore the product is used.

In some embodiments, it may be preferable for the initial dry state ofthe wetness indicator composition to be completely white with no sign ofany coloration. This can be accomplished by using synthetic ingredientsthat can be synthesized to be white. This is converse to the use ofrosins and polymerized rosins which are natural materials most commonlyderived from trees. These natural rosins tend to be more yellow in colorin the dry state and not white. But, in certain cases, the addition ofwhite opacifiers like titanium dioxide or sodium aluminum silicate canhelp hide the yellow coloration from the use of natural materials.

The binding material may immobilize the colorant when in its initialcolor state. How the binding material immobilizes the colorant when inits initial color state depends upon both what the binding material andcolorant are. For example, the first binding material may work by one ormore forces selected from the group consisting of adhesion, hydrogenbonding, ionic, polar covalent bonding, Van der Waals forces,dipole-dipole forces, London dispersion forces and combinations thereof.

The binding agent may be employed in compositions at levels which areeffective at immobilizing and stabilizing the colorant in its firststate, including from about 1% to about 90%, from about 10% to about75%, and from about 20% to about 65%, by weight of the composition.

The binding matrix may comprise a first and second binding agent. Thesecond binding agent may be any material which may immobilize thecolorant when the colorant is in its final color state. Thisimmobilization helps to bind the colorant within the wetness indicatorcomposition to prevent it from leaching to other regions of the diapersuch as the diaper core. It should be noted that similar to the firstbinding agent, the second binding agent can function not only to hinderthe leaching of the colorant outside of the wetness indicatorcomposition but can also aid in bonding the entire wetness indicatorcomposition to the material of interest within the absorbent article.For example, the second binding agent may aid in bonding the wetnessindicator composition to the backsheet of the diaper. There are variousmaterials which may be suitable for use as an additional binding agentfor the liquid-activated formulations of the present invention.

In one embodiment, a binding agent may be selected from, but are notlimited to, the second binding agents disclosed in U.S. Pat. No.6,904,865 to Klofta.

In one optional embodiment of the present invention, a binding agent isselected from the group consisting of quaternary ammonium saltcompounds, cationic clay, polyacrylic acid polymers, organic acids, andcombinations thereof. Examples of suitable quaternary ammonium compoundsinclude, but are not limited to,dimethyl(2-ethylhexylhydrogenatedtallowalkyl)ammonium methyl sulfate,cocoalkylmethyl[ethoxylated(15)]ammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethyl ammonium methyl sulfate,octadecyltrimethyl ammonium chloride, dicocoalkyldimethly ammoniumchloride, di(hydrogenated tallowalkyl)dimethyl ammonium chloride, anddistearyldimethyl ammonium chloride.

It should be noted that the counter anion associated with the quaternarycompound, or any binding agent having one or more cationic group, is notspecifically limited to chloride. Other anions can also be employed andnon-limiting examples include methyl sulfate and nitrite. Similarly, anysuitable counter cation, such as, but not limited to, sodium, potassium,calcium, magnesium, zinc, protons, ammonium, substituted ammonium andthe like, may be associated with a binding agent having one or moreanionic groups.

The second binding material may immobilize the colorant when in itsfinal color state. How the second binding material immobilizes thecolorant when in its final color state depends upon the chemicalcomposition of both the second binding material and colorant. Forexample, if the colorant's final color state is that of an anionic longchain molecule and the second binding material is a cationic molecule,then the bond formed may be, for example, an ionic bond, a covalentbond, or the like, or combinations of the relevant bonding forces.Another example, if the colorant's final color state is that of acationic molecule, and the second binding material is an anionic longchain molecule, then the bond formed may be, for example, an ionic bond,covalent bond, or the like, or combinations of the relevant bondingforces.

In one embodiment of the present invention the second binding agentimmobilizes the colorant when the colorant is in its final color stateby one or more selected from the group consisting of covalent bonding,ionic bonding, Van der Waals, and combinations thereof.

Without wishing to be bound by theory, it is believed that when thecolorant is an anion in its final color state and the second bindingagent is a cation or the colorant is a cation in its final color stateand the second binding agent is an anion, the second binding agent formsan ionically bonded coacervate with the colorant. For example, when thefinal state associated with a colorant's final color state is the pH ofurine, contacting the colorant with urine will change the colorant toits final color state, i.e. an anion, and this forms an ionic bond withthe second binding agent, which is a cation. The coacervate formation isdue to the strong coulombic interaction between the opposite charges ofthe colorant and the second binding agent. The coacervate formed betweenthe colorant and the second binding agent neutralizes the charge in bothspecies and dramatically reduces both of their solubilities in polarsolvents such as water or urine while the coacervate's solubility in thematrix remains high due to this charge neutralization and thecoacervate's more lipophilic nature. Both of these effects dramaticallyinhibits the leaching of the colorant from the matrix. The increasedlipophilicity of the coacervate leads to increased intermolecularbonding forces between the coacervate and components of the matrix.These intermolecular forces may further limit the diffusion and mobilityof the colorant into an fluid environment such as water or urine.

In certain optional embodiments of the present invention, use ofcationic quaternary ammonium compounds, quaternary polymers, andcombinations thereof as the second binding agent may also function todarken or intensify the color change of certain colorants, especiallythose belonging to the sulfonephthalein class of pH indicators. Withoutwishing to be bound by theory, it is believed this darkening is due toseveral possible factors: 1) alkaline impurities within the quaternaryammonium raw material, 2) absorption shifting and absorptivitycoefficient increases due to coacervate formation and/or 3) increasedformation of the colorant in its final color state.

The second binding agent may be employed in compositions at levels whichare effective at immobilizing the colorant in its second state,including from about 0.5% to about 20%, from about 0.5% to about 10%,and from about 0.1% to about 5%, by weight of the composition, such asthe liquid activation formulation.

Hot Melt Adhesives

In some embodiments, the binding agent may be a hot melt adhesive.Additional components of a hot melt adhesive binding matrix may includebase polymers, tackifiers, waxes, rubbers, solvents, wetting agents,and/or anti-oxidants. Examples of base polymers used in hot meltadhesives may include ethylene-vinyl acetate (EVA) copolymers;ethylene-acrylate copolymers; ethylene-vinylacetate-maleic anhydrideterpolymer; ethylene-acrylate-maleic anhydride terpolymer; polyolefinssuch as low density and high density polyethylene, atactticpolypropylene, oxidized polyethylene, polybutene-1; amorphouspolyolefins like amorphous atactic propylene (APP), amorphouspropylene/ethylene (APE), amorphous propylene/butane (APB), amorphouspropylene/hexane (APH), and amorphous propylene/ethylene/butane;polyamides; styrene block copolymers (SBC); styrene/acrylic polymers andmodified styrene/acrylic polymers; polycarbonates; silicone rubbers;polypyrrole based polymers; thermoplastic elastomers like natural andsynthetic polyisoprene, polybutadiene rubber, butyl rubber, chloroprenerubber, ethylene-propylene rubber, epichlorohydrin rubber, polyacrylicrubber, polyether block amides; polymers of acrylates, alkyd resins,amides, amino resins, ethylene co-terpolymer resins such as EVA, epoxyresins, fluoropolymers, hydrocarbon resins, phenols, polyesters,olefins, polyurethanes, silicones and functionalized silicones,polystyrene and polyvinyls.

Tackifiers suitable for hot melt adhesives include, without beinglimited to, natural resins like copals like gum copal, dammars, mastic,and sandarac; rosins and their derivatives; terpenes and modifiedterpenes; aliphatic, cycloaliphatic, and aromatic resins like C5aliphatic resins, C9 aromatic resins, and C5/C9 aromatic/aliphaticresins, hydrogenated hydrocarbon resins and their mixtures.

Waxes suitable for hot melt adhesives include, without being limited to,mineral waxes like paraffin and microcrystalline waxes; polyethylenewaxes; polyethylene glycol type waxes; oxidized polyethylene waxes;highly branched polymer waxes like Vybar™ from Baker Hughes; fatty amidewaxes; natural and synthetic waxes like beeswax, soywax, carnuba,ozokerite, ceresin; waxes derived from both the Fisher-Tropsch andZiegler-Natta processes; and silicone waxes.

Additional additives for adhesives and hot melt adhesives may includeplasticizers, like glyceryl tribenzoate, phthalates, paraffin oils, andpolyisobutylene; UV stabilizers; biocides and antimicrobialpreservatives; antioxidants, like BHT, phosphites and phosphates;antistatic agents; rosins and their derivatives; pigment, particle andpowder wetting agents like polyhydroxystearic acid, polyglyceryl-4isostearate, hexyl laurate, isopropyl myristate, propylene carbonate,isononyl isononanoate, glyceryl behenate/eicosadioate,trihydroxystearin, C12-15 alkyl benzoate, triethoxycaprylysilane, castoroil; and viscosity modifiers. Optionally, solvents like mineral oil,isoparaffins, alkanes like hexane, silicone fluids, esters, alcohols,polyethylene glycols, glycerin, glycols, and water can be added toreduce the viscosity of the composition or to increase the solubility ofother ingredients or change other strategic properties of the wetnessindicator composition.

Colorants

The liquid activated formulations which are utilized in this inventioncomprise a liquid-activated colorant. A colorant may be a dye, an ink, apigment, or a pH indicator. The liquid activated colorant can be solublewithin the wetness indicator composition and in certain cases, it can besuitable to homogenerously suspend or disperse the colorant within thewetness indicator composition. As noted, the colorant changes color uponcoming in contact with water or urine. In some embodiments, theliquid-activated formulation may further comprise a permanent colorantthat does not change color upon coming in contact with water or urine.

Some representative examples of liquid-activated colorants that can beused in the practice of this invention include: Malachite green,brilliant green, crystal violet, erythrosine B, methyl green, methylviolet 2D, picric acid, naphthol yellow S, quinaldine red, eosine Y,metanil yellow, m-cresol purple, thymol blue, xylenol blue, basisfuchsin, eosin B, 4-p-aminophenol(azo)benzenesulphonic acid-sodium salt,cresol red, m-cresol red, m-cresol purple, martius yellow, phloxine B,methyl yellow, bromophenol blue, congo red, methyl orange,bromochlorophenol blue (water soluble or free acid form), ethyl orange,fluorocene WS, bromocresol green, chrysoidine, methyl red sodium salt,alizarine red S—H2O, cochineal, chlorophenol red, bromocresol purple,4-naphtha, alizarin, nitrazine yellow, bromothymol blue, brilliantyellow, neutral red, rosalic acid, phenol red, 3-nitro phenol, orangeII, phenolphthalein, o-cresolphthalein, nile blue A, thymolphthalein,aniline blue WS, alizarine yellow GG, mordant orange, tropaolin O,orange G, acid fuchsin, thiazol yellow G, indigo carmine, cresol red,methyl red, p-nitrophenol, and alizarin yellow R. In certain instances,it is advantageous to use the free acid form, free base form, or saltform of the colorants.

Additional water-soluble colorants may include FD&C Blue No. 1, FD&CBlue No. 2, FD&C Green No. 3, FD&C Red No. 40, FD&C Red No. 4, FD&CYellow No. 5, FD&C Yellow No. 6, C.I. Food Blue 5, and C.I. Food Red 7,D&C Yellow No. 10, D&C Yellow No. 7, D&C Yellow No. 2, D&C Yellow No. 8,D&C Orange No. 4, D&C Red No. 22, D&C Red No. 28, D&C Red No. 33, D&CGreen No. 8, D&C Green No. 5, D&C Brown No. 1, and any combinationthereof. Preferably, the colorant is soluble within the wetnessindicator composition, but, as noted in certain instances, the colorantcan function as intended by homogenerously suspending or dispersing itwithin the wetness indicator composition.

Many of these aforementioned colorants do not change colors whencontacted by an aqueous solution like urine. These are referred to aspermanent colorants which can function to change the color hue of thewetness indicator composition of either its dry state or color changedstate after contact with a fluid like urine. Some examples of oilsoluble permanent colorants include D&C Yellow No. 11, D&C Red No. 17,D&C Red No. 21. D&C Red No. 27, D&C Violet No. 2, D&C Green No. 6, andD&C Orange No. 5. These permanent and oil soluble colorants can not onlychange the color hue of the wetness indicator composition in either thedry or wet state, but they can be advantageous due to their reducedsolubility in hydrophilic liquids like urine. Thus, their leaching isinhibited and they possess a higher probability of remaining boundwithin the wetness indicator composition after being wetting with anaqueous liquid like urine.

Additional suitable fluid colorants include water soluble colorants likedirect dyes, acid dyes, base dyes, and various solvent-solublecolorants. Dispersed or suspended pigment colorants can also be employedinto these wetness indicator compositions (liquid-activatedformulations). Examples include, but are not limited to, C.I. AcidYellow 73, C.I. Solvent Yellow 94, C.I. Acid Yellow 74, C.I. SolventOrange 32, C.I. Solvent Red 42, C.I. Acid Orange 11, C.I. Solvent Red72, C.I. Pigment Orange 39, C.I. Solvent Orange 18, C.I. Acid Red 87,C.I. Solvent Red 43, C.I. Pigment Red 90:1, C.I. Solvent Red 44, C.I.Solvent Red 45, C.I. Solvent Orange 16, C.I. Acid Red 91, C.I. Acid Red98, C.I. Acid Red 92, C.I. Solvent Red 48, C.I. Pigment Red 174, C.I.Acid Red 95, C.I. Solvent Red 73, C.I. Pigment Red 191, C.I. Acid Red51, C.I. Food Red 14, C.I. Pigment Red 172, C.I. Solvent Red 140, C.I.Acid Red 93, C.I. Solvent Red 47, C.I. Acid Red 94, C.I. Solvent Red141, C.I. Mordant Violet 25, C.I. Solvent Orange 17, C.I. Solvent Red46, D&C Red 27(C.I. 45410:1), D&C Orange 5(C.I. 45370:2), andcombinations thereof. More preferred fluid colorants are selected fromthe group consisting of D&C Red 27, D&C Orange 5, and combinationsthereof.

Additional suitable colorants may include bromopyrogallol red,bromoxylenol blue, methylene blue, monoazo dyes such as acid alizarinvoliet N, monoazo pyrazoline dyes (such as acid yellow 34), diazo dyes(such as acid black 24), anthraquinone dyes (such as acid black 48),amphoteric anthraquinone dyes (such as acid blue 45),triphenylmethanedyes (such as acid fuchsin), phthalein type dyes (such aso-cresolphthalein), xanthene dyes (such as 2′7′ dichlorofluoresceineosin B), heterocyclic acridine aromatics (such as acridine orange),diphenylmethane dyes (such as auramine O), triphenylmethane dyes (suchas basic fuchsin), cationic thiazine dyes (azure C), cationicanthraquinone dyes such as basic blue 47, phthalocyanine type dyes (suchas strazon orange G), anthraquinone type (such as alizarin), neutralcomplex dyes (such as azure A eosinate), terpene type dyes (such astrans-beta-carotene), as well as combinations including at least one ofthe foregoing dyes. Examples of colorants further include, but are notlimited to, organic dyes, inorganic pigments, colored macromolecules,colored nanoparticles and materials. Examples of dyes include acridinedyes, anthraquinone dyes, arylmethane dyes, azo dyes, nitro dyes,nitroso dyes, phthalocyanine dyes, quinone-imine dyes, Aazin dyes,Indophenol dyes, oxazin dyes, Oxazone dyes, Thiazole dyes, xanthenedyes, Fluorene dyes, fluorone dyes, rhodamine dyes. Examples of pigmentsinclude Cadmium pigments: cadmium yellow, cadmium red, cadmium green,cadmium orange; Carbon pigments: carbon black (including vine blac, lampblack), ivory black (bone char); Chromium pigments: chrome yellow andchrome green; Cobalt pigments: cobalt violet, cobalt blue, ceruleanblue, aureolin (cobalt yellow); Copper pigments: Azurite, Han purple,Han blue, Egyptian blue, Malachite, Paris green, Phthalocyanine Blue BN,Phthalocyanine Green G, verdigris, viridian; Iron oxide pigments:sanguine, caput mortuum, oxide red, red ochre, Venetian red, Prussianblue; Clay earth pigments (iron oxides): yellow ochre, raw sienna, burntsienna, raw umber, burnt umber; Lead pigments: lead white, cremnitzwhite, Naples yellow, red lead; Mercury pigments: vermilion; Titaniumpigments: titanium yellow, titanium beige, titanium white, titaniumblack; Ultramarine pigments: ultramarine, ultramarine green shade; Zincpigments: zinc white, zinc ferrite. Other examples include alizarin,alizarin crimson, gamboge, cochineal red, rose madder, indigo, Indianyellow, Tyrian purple, organic quinacridone, magenta, phthalo green,phthalo blue, pigment red.

Hydrochromic Ionic Compound

The hydrochromic ionic compound is typically a reactive ionic compound,such as an ionizing salt. Some representative examples of hydrochromicionic compounds that can be employed in the practice of this inventioninclude: lithium hydrogen sulfate, lithium hydrogen carbonate, potassiumhydrogen sulfate, potassium hydrogen carbonate, rubidium hydrogensulfate, rubidium hydrogen carbonate, cesium hydrogen sulfate, cesiumhydrogen carbonate, sodium hydrogen sulfate, sodium hydrogen carbonate,sodium carbonate, cesium hydroxide, lithium hydroxide, potassiumhydroxide, calcium hydroxide, magnesium hydroxide, sodium thiosulfatepenta hydrate, sodium hydroxide, rubidium hydroxide, cobalt chloride,cobalt nitrate, copper sulphate copper nitrate, iron (II) sulfate, iron(III) sulfate, iron (II)chloride, iron (III) chloride, citric acid,monosodium dihydrogen citrate, disodium hydrogen citrate, trisodiumcitrate, gluconic acid, sodium gluconate, glycolic acid, sodiumglycolate, malic acid, sodium malate, maleic acid, sodium maleate,acetic acid, phosphoric acid, trisodium phosphate, sodium dihydrogenphosphate, disodium hydrogen phosphate, monostearyl phosphate, monocetylphosphate, monostearyl citrate, hydrochloric acid, nitric acid, sulfuricacid and combinations thereof.

Opacifiers

The opacifiers that can be utilized in the liquid activated formulationsof this invention can be porosigens or antiporosigens and are typicallywhite powders when they are in the form of dry solids (before beingincorporated into the ink formulation). In the cases where theopacifiers act as porosigens they allow for liquid transmission throughcoatings which are applied to a substrate, such as a coating which isprinted on the outer layer of a diaper. In other words, the porosigen isa compound which allows for liquid to be transmitted through it whichfacilitates liquid transmission throughout the coating. In the case ofantiporosigens liquid transmission is attained by virtue of liquidpermeable interstices which are formed in proximity to theantiporosigens by virtue of disrupting the structure of liquid barriermaterials. In other words, the antiporosigens cause holes to be presentin the dry coating structure which are of a size and structure whichallows for liquid to flow through the coating. Some representativeexamples of opacifiers that can be utilized include titanium dioxide,calcium carbonate, calcium hydroxide, sodium silicate, potassiumsilicate, silica, starch, ethocell, methocell, barium carbonate, bariumsilicate, calcium silicate, aluminum silicate, aluminum hydroxide, zincoxide, sodium aluminum silicate like Evonik's Sipernat™ 820a, zirconiumsilicate, magnesium aluminum silicate, and aluminum oxide. Suitablepolymeric opacifiers include the styrene/acrylate copolymers likeOpulyn™ 301 from Rohm and Haas, and the SunSphere™ line of opacifiers,also from Rohm and Haas.

Additional Ingredients

Additional ingredients may include, for example, a stabilizer, asurfactant, a structural adjunct, and/or solvents. When present, suchingredients are typically employed in the composition at levels that areeffective at providing the benefits of the ingredient or ingredients,such as, for example, from about 0.001% to about 50%, from about 0.1% toabout 40%, or from about 1% to about 35%, by weight of the composition.Solvents may include a liquid, gel or semi-solid material. The solventmay be water, a thixotropic material, paste, an alcohol, ethylene glycolmonobutyl ether, mineral oil, esters, silicone fluids, isoparaffins,alkanes like hexane, toluene, xylenes, low molecular weight polyethyleneglycols like PEG-200, glycerin, glycols, a non-flammable solvent, anadhesive material, or other organic species. Preferred non-aqueoussolvents may comprise alcohols, acetates, and combinations thereof. Thealcohol solvents are preferably selected from the group consisting ofiso-propyl alcohol, n-propyl alcohol, ethanol, methanol, andcombinations thereof. Likewise, suitable acetate solvents include, butare not limited to, isopropyl acetate, n-propyl acetate, andcombinations thereof.

Other suitable solvents that may be effective include water, aqueousdetergent solutions, acidic water solutions, alkaline water solutions,isopropanol, ethanol, methyl-ethyl ketone, acetone, toluene, hexane,ethyl 15 acetate, acetic acid (vinegar), cetyl alcohol (fatty alcohol),dimethicone silicone, isopropyl lanolate, myristate, palmitate, lanolin,lanolin alcohols and oils, octyl dodecanol, oleic acid (olive oil),panthenol (vitamin B-complex derivative), stearic acid and stearylalcohol, butylene glycol and propylene glycol, cyclomethicone (volatilesilicone), glycerin, aloe, petrolatum, and so forth. Adhesives that maybe useful include, for example, those based on alkyds, animal glues,casein glues, cellulose acetates, cellulose acetate butyrates, cellulosenitrates, ethyl celluloses, methyl celluloses, carboxy methylcelluloses, epoxy resins, furane resins, melamine resins, phenolicresins, unsaturated polyesters, polyethylacrylates,poly-methylmethacrylates, polystyrenes, polyvinylacetates,polyvinylalcohols, polyvinyl acetyls, polyvinyl chlorides, polyvinylacetate chlorides, polyvinylidene copolymers, silicones, starched basedvegetable glues, urethanes, acrylonitrile rubbers, polybutene rubbers,chlorinated rubbers, styrene rubbers, and so forth. Waxes such as, forexample, polyolefin waxes, bees waxes, and so forth, and gels such as,for example, glycol dimethacrylate, chitosan, polyacrylates,hydroxypropylcellulose, gelatin, and so forth, may also be useful toeffect the color change.

Surfactants that are suitable for the present invention may include, forexample, ethoxylated alcohols, fatty alcohols, high molecular weightalcohols, ethoxylated sorbitan esters like Tween™ 40 from Croda, theethoxylated pareth surfactants like Performathox™ 450 from New PhaseInc., esters, polymers and other natural and synthetic waxes orolefininc materials as known in the art; anionic and cationicsurfactants, alkoxylated alkylates such as PEG-20 stearate, endgroup-capped alkoxylated alcohols, alkoxylated glyceryl and polyglycerylalkylates such as PEG-30 glyceryl stearate, glyceryl alkylates such asglyceryl stearate, alkoxylated hydrogenated castor oil, alkoxylatedlanolin and hydrogenated lanolin, alkoxylated sorbitan alkylates, sugarderived surfactants such as the alkyl glycosides and sugar esters,poloxamers, polysorbates, and sulfo succininc acid alkyl esters. Furtherexamples include nonionic surfactants and amphoteric surfactants and anycombination thereof; specific-diethylhexylsodiumsulfosuccinate,available as MONOWET MOE75 from Uniqema, the sodium dioctylsulfosuccinate line of surfactants like Aerosol™ OT-100 from Cytec Inc.Another example is 4-1-aminoethylphenolpolyoxyethylenefattyethers,polyoxyethylene sorbitan esters, TWEEN, and polyoxyethylene fatty acidesters.

Other suitable surfactants may be neutral block copolymer surfactants,which can be selected from polyoxypropylene-polyoxyethylene blockcopolymer, poly [poly(ethylene oxide)-block-polypropyleneoxide)]copolymer or propylene glycol-ethylene glycol block copolymer.Suitable neutral polymeric surfactants include TWEEN surfactants, suchas TWEEN 20 surfactant, TWEEN 40 surfactant and TWEEN 80 surfactant, andTRITON X-100 surfactant, which are available from Sigma-Aldrich,Incorporated. Other suitable neutral surfactants include polyethylenelauryl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene oleylphenyl ether, polyoxyethylene sorbitan monolaurate, polyethylene glycolmonostearate, polyethylene glycol sorbitan monolaurate,polyoxyethylenesorbitan monopalmitate, polyoxyethylenesorbitanmonostearate, polyoxyethylenesorbitan monooleate,polyoxyethylenesorbitan trioleate, polypropylene glycol sorbitanmonolaurate, polyoxypropylenesorbitan monopalmitate,polyoxypropylenesorbitan monostearate, polyoxypropylenesorbitanmonooleate, polyoxypropylenesorbitan trioleate, polyalkyne glycolsorbitan monolaurate, polyalkyne glycol sorbitan monopalmitate,polyalkyne glycol sorbitan monostearate,polyalkyne glycol sorbitanmonooleate, polyalkyne glycol sorbitan trioleate and mixtures of suchneutral surfactants.

The neutral block copolymer based surfactants include FLURONIC seriesblock copolymers, such as PLURONIC P84 or FLURON IC P85 surfactants,which are available from BASF Corporation.

Other suitable neutral block copolymer based surfactants includenonylphenol ethoxylates, linear alkyl alcohol ethoxylate, ethyleneoxide-propylene oxide block copolymer, polyoxypropylene-polyoxyethyleneblock copolymer, polyalkylene oxide block copolymer, polyalkylene oxideblock copolymer and propylene glycol-ethylene glycol block copolymer.

It may be desirable to include a stabilizer when the colorant is a pHindicator and when the absorbent article could be stored underconditions of high humidity and high temperature. The inclusion of astabilizer is also especially important for new diaper designs wherematerials and/or chemicals are present that could potentiallyprematurely activate the color change of the colorant within the inkformulation.

In one embodiment of the present invention, the stabilizer is an acidicstabilizer. In another embodiment of the present invention, thestabilizer is a basic stabilizer. The inclusion of a stabilizer, whilenot wishing to be limited by theory, is believed to play a role instabilizing the colorant against premature changes caused by exposure tohumid environments and/or certain components of the diaper, bymaintaining a stable pH, such as a low pH environment with an acidicstabilizer, around the colorant even when the system is exposed to highhumidity and/or certain components of the diaper. This maintenance of astable pH environment keeps the colorant, especially when the colorantis a pH indicator, in its initial dry color state. Desiccants can alsostabilize the composition by trapping free water that could prematurelyactivate the wetness indicator composition. Examples of suitabledesiccants include silica gel, bentonite clays, activated alumina,calcium sulfate, copper(II) sulfate, and magnesium sulfate.

One of the key properties of a properly functioning wetness indicator isfor it to maintain its dry state color during a variety of storage andpackaging conditions while still undergoing a noticeable color change ina reasonable amount of time after being contacted by urine. The colorantshould also remain stable to various chemicals and materials that mightbe present in the diaper. Although acidic moieties present in the rosinsas part of the matrix can aid in preserving the dry state color,additional stabilizer ingredients have been found to be necessary withsome new diaper designs where high pH components within the diaper cancause the undesirable and premature color change activation of thecolorant. To maintain the colorant in its acidic dry state color, acidsof suitable strength should be added. Suitable strength is defined bythe colorant and pH range where it changes color. The colorant's pKavalue is especially important in assessing the characteristics of thechosen stabilizer.

For a pH indicator colorant like the sulfonephthalein class whichincludes bromocresol green which changes color between a pH of 3.8 and5.4 (See “The Sigma-Aldrich Handbook of Stains, Dyes and Indicators,” byFloyd J. Green, Aldrich Chemical Co., Milwaukee, Wis.), the stabilizershould contribute suitably strong acidic moieties to keep thebromocresol green in its yellow state within the matrix. Although manystrong acids like sulfuric acid and hydrochloric acid have suitably lowpH's to accomplish this, their solubilities are low in these anhydrousmatrices. In addition, their high acidity can chemically decompose thestructures of some of the components present in the wetness compositionand diaper. As noted, carboxylic acid moieties present in the matrixingredients like rosins or polymerized rosins can also aid inmaintaining the colorant in its acidic color state but carboxylic acidsare typically too weak to maintain the dry yellow state of bromocresolgreen if it is exposed to high humidities and/or high pH componentswithin new diaper designs. To increase the strength of the carboxylicacids, one can add electron withdrawing groups between the carboxylicacid moiety and another portion of the molecule. Although a fatty acidlike stearic acid can aid in preserving the dry state color, it can bemade more effective by making it a stronger acid by insertingpolyoxyethylene groups between the carboxylic acid group and the alkylchain. These types of molecules are called ether carboxylates and theseacidic molecules can be effective in maintaining the dry state acid formof the pH indicator colorant like bromocresol green. In addition, thealkyl group present in these ether carboxylates increases theirsolubility in the wetness indicator matrix. Finally, the ethercarboxylate's surfactancy can aid in increasing the kinetics foractivating the color change of the wetness indicator composition afterit is contacted by urine.

Other suitable stabilizers are those of the monoalkyl phosphate freeacid and dialkyl phosphate free acid types. The phosphate acid moiety isa stronger acid than the carboxylic acid group and thus can be moreeffective in maintaining the low pH environment required to keep the pHindicator colorant in its dry acidic state. These alkyl phosphate freeacids have been found to be particularly effective in preserving the drystate color of the bromocresol green colorant from premature activationas caused by high humidities or destabilizing materials and/or chemicalspresent in new diaper designs. Particularly effective alkyl phosphatefree acids are stearyl phosphate free acid, cetyl phosphate free acid,and cetearyl phosphate free acids. Thus, the phosphate is a suitablystrong acid to maintain the pH indicator colorant in its acidic drystate form, and the lipophilic alkyl moiety aids in increasing itssolubility within the wetness indicator composition. In addition, thesurfactant nature of the alkyl phosphate free acids can aid in speedingup the kinetics of the color change after the wetness indicatorcomposition is contacted by urine.

Other acidic stabilizers which are particularly effective in stabilizingthe wetness indicator formula to high humidity and/or destabilizingcomponents within the diaper include, but are not limited to: organicacids, such as, but not limited to, fatty acids such as stearic acid,palmitic acid, lower molecular weight acids such as citric acid, malicacid, maleic acid, lactic acid, glycolic acid, gluconic acid, fumaricacid, adipic acid, ascorbic acid, and salicylic acid; acid esters, suchas, citrate esters, e.g., monostearyl citrate and monocetyl citrate,glycolate esters, lactate esters; phosphorus containing organic acids,such as, monostearyl phosphate and monocetyl phosphates; ethercarboxylic acids; N-acyl sarcosinic acids; N-acyl glutamic acids; N-acylethylenediaminetriacetic acid; alkane sulfonic acids; alpha-olefinsulfonic acids; alpha-sulfonic acid fatty acid methyl esters; sulfateesters; inorganic acids, such as, phosphoric acid; and combinationsthereof. Examples of suitable basic stabilizers include, but are notlimited to: monoethanolamine; diethanolamine; triethanolamine;dipropylenetriamine; diiosopropyl amine; organic diamines, such as, butnot limited to, 1,3-bis(methylamine)-cyclohexane, 1,3-pentanediamine;inorganic bases, such as, but not limited to, sodium hydroxide,magnesium hydroxide, and combinations thereof.

The stabilizer, when present is typically employed in compositions atlevels which are effective at stabilizing the colorant, from about0.001% to about 30%, from about 0.1% to about 15%, and also from about1% to about 10%, by weight of the composition.

The present invention may include structural adjuncts, such as HLB(hydrophilic lipophilic balance) modifiers, viscosity modifiers,hardening agents, wetting agents, anti-oxidants, anti-leaching aids,and/or colorant solubilizers. Suitable ones may include polymericthickeners such as block copolymers having polystyrene blocks on bothends of a rubber molecule, the aforementioned copolymers of ethylene andvinyl acetate (EVA), hydrogenated castor oil, polymers, metals salts offatty acids, silicas and or derivatized silicas, organoclays such asmodified and unmodified hectorites and bentonites, modified clays suchas modified laponite clays, dibenzylidene sorbitol, alkyl galactomannan,aluminium magnesium hydroxide stearate/oil blends and lauroyl glutamicdibutylamide. Hardening agents may include the aforementioned waxes, C14-22 fatty alcohols, C14-22 fatty acids, C23-60 carboxylic acids,hydrogenated vegetable oils, polymers, sorbitan esters and other highmolecular weight esters.

The wetting agent can be a surfactant or a mixture of surfactants. Thesurfactants can be non-ionic surfactants or ionic surfactants. The ionicsurfactants can be either positively charged or negatively charged. Theexamples of non-ionic surfactants include alkyl poly(ethylene oxide)such as copolymers of poly(ethylene oxide) and polypropylene oxide)(commercially called Poloxamers or Poloxamines), alkyl polyglucosidessuch as octyl glucoside and decyl maltoside, fatty alcohols such ascetyl alcohol, oleyl alcohol, cocamide MEA and cocamide DEA. Theexamples of ionic surfactants include anionic (e.g., based on sulfate,sulfonate or carboxylate anions) surfactants such as s (SDS), ammoniumlauryl sulfate and other alkyl sulfate salts, Sodium laureth sulfate,also known as sodium lauryl ether sulfate (SLES), Alkyl benzenesulfonate, Soaps, or fatty acid salts; and Cationic (e.g., based onquaternary ammonium cations) surfactants such as Cetyl trimethylammoniumbromide (CTAB) a.k.a. hexadecyl trimethyl ammonium bromide, and otheralkyltrimethylammonium salts, Cetylpyridinium chloride (CPC),Polyethoxylated tallow amine (POEA), Benzalkonium chloride (BAC),Benzethonium chloride (BZT); or Zwitterionic (amphoteric) surfactantssuch as Dodecyl betaine, Dodecyl dimethylamine oxide, Cocamidopropylbetaine, Coco ampho glycinate. Alternatively, the wetting agents mayalso be hydrophilic molecules. The hydrophilic molecules may be smallmolecules such as sucrose, glucose and glycerol. Thehydrophilicmolecules may also be polymers such as polyethylene glycoland its copolymers.

Substrate

In one embodiment of the present invention, the liquid-activatedformulation of the present invention may be on and/or in a substrate.When present on a substrate, the liquid-activated formulation willtypically be placed on and/or in a substrate where the substrate will becontacted by a liquid, such as water, urine, menses, blood and the like.The substrate may include, but is not limited to, a structuralcomponent, such as woven fabrics, nonwoven fabrics, films, sponges, andcombinations thereof. The substrate may comprise synthetic and/ornatural materials. In one embodiment of the present invention theoptional substrate may be an article in its own right, such as, acontinuous nonwoven fabric. In another embodiment of the presentinvention the substrate to which the liquid-activated formulation may beapplied or otherwise affixed comprises any one, or a combination of,structural components of an absorbent article, including, but notlimited to, the backsheet, topsheet, fasteners, absorbent material,etc., or may be a separate element added or applied to the product. Inone optional embodiment of the present invention the liquid-activatedformulation is applied to the absorbent article as a whole. In someembodiments, the liquid-activated formulation is a single layer. Such asingle layer may be applied to a substrate or structural component. Insome embodiments, the single-layer formulation may be disposed betweenthe backsheet and the absorbent core, in other embodiments, between thetopsheet and the absorbent core.

The indicating material may be coated over a surface of said substrateas either a) a monochromic color scheme alone, bi-chromic, or multiplecolors, b) in various shapes and sizes, c) graphics of patterns or alphanumeric symbols and words, or combinations thereof. The color transitionmay be from being either a) colored to uncolored, b) uncolored tocolored, c) colored to different colored, or d) a combination of a) andb) and c).

The manufacture of substrates, absorbent articles and structuralcomponents thereof, for use herein form no part of this invention. Thefollowing discussion is for convenience of formulation, but is notintended to limit the type of substrate used herein.

In one embodiment of the present invention the disposable absorbentarticle is a disposable diaper. Typically, modern disposable diaperscomprise a liquid pervious topsheet a liquid impervious backsheet; anabsorbent core which may be positioned between at least a portion of thetopsheet and the backsheet; side panels; elasticized leg cuffs; anelastic waist feature; and a fastening system. In one embodimentopposing sides of the disposable diaper may be seamed or welded to forma pant. This allows the article to be used as a pull-on type diaper,such as a training pant. Additional illustrative, but non-limiting,information on construction, assembly, and the various components(including backsheets, dusting layers, upper and lower covering sheets,and webs) of disposable diapers may be found in U.S. Pat. No. 3,860,003to Buell; U.S. Pat. No. 5,151,092 to Buell; U.S. Pat. No. 5,221,274 toBuell; U.S. Pat. No. 5,554,145 to Roe et al. on Sep. 10, 1996; U.S. Pat.No. 5,569,234 to Buell et al.; U.S. Pat. No. 5,580,411 to Nease et al.;U.S. Pat. No. 6,004,306 to Robles et al.; U.S. Pat. No. 5,938,648 toLaVon et al.; U.S. Pat. No. 5,865,823 to Curro; U.S. Pat. No. 5,571,096to Dobrin et al.; U.S. Pat. No. 5,518,801 to Chappell, et al.; U.S. Pat.No. 4,573,986 to Minetola et al.; U.S. Pat. No. 3,929,135, to Thompson;U.S. Pat. No. 4,463,045 to Ahr, et al.; U.S. Pat. No. 4,609,518 to Curroet al.; U.S. Pat. No. 4,629,643 to Curro et al.; U.S. Pat. No. 5,037,416to Allen et al.; U.S. Pat. No. 5,269,775 to Freeland et al.; U.S. Pat.No. 4,610,678 to Weisman et al.; U.S. Pat. No. 4,673,402 to Weisman etal.; U.S. Pat. No. 4,888,231 to Angstadt; U.S. Pat. No. 5,342,338 toRoe; U.S. Pat. No. 5,260,345 to DesMarais et al.; U.S. Pat. No.5,026,364 to Robertson; U.S. Pat. No. 3,848,594 to Buell; U.S. Pat. No.4,846,815 to Scripps; U.S. Pat. No. 4,946,527 to Battrell; U.S. Pat. No.4,963,140 to Robertson et al.; U.S. Pat. No. 4,699,622 to Toussant etal.; U.S. Pat. No. 5,591,152 to Buell et al.; U.S. Pat. No. 4,938,753 toVan Gompel, et al.; U.S. Pat. No. 5,669,897 to LaVon, et al.; U.S. Pat.No. 4,808,178 to Aziz et al.; U.S. Pat. No. 4,909,803 to Aziz et al.:U.S. Pat. No. 4,695,278 to Lawson and U.S. Pat. No. 4,795,454 issued toDragoo; and U.S. Ser. No. 10/770,043 to LaVon; U.S. Pat. No. 7,318,820to LaVon et al.; U.S. Pat. No. 6,962,578 to LaVon; U.S. Pat. No.7,377,914 to LaVon; Ser. No. 11/715,976 to LaVon; Ser. No. 10/880,128 toLaVon; Ser. No. 11/131,799 to LaVon et al., Ser. No. 11/133,818 to LaVonet al.; Ser. No. 11/135,689 to LaVon; Ser. No. 11/140,888 to LaVon etal.; Ser. No. 11/158,563 to LaVon et al.; Ser. No. 11/159,916 to LaVonet al., Ser. No. 11/197,197 to LaVon et al.; Ser. No. 11/210,345 toLaVon et al.; Ser. No. 11/224,462 to LaVon et al.; Ser. No. 11/231,511to LaVon et al.; Ser. No. 11/231,512 to LaVon et al.; Ser. No.11/231,500 to LaVon et al.; Ser. No. 7,320,684 to LaVon et al.; Ser. No.11/286,934 to LaVon et al.; Ser. No. 11/286,614 to LaVon; Ser. No.11/286,612 to LaVon; Ser. No. 11/700,585 to LaVon et al.; Ser. No.11/709,500 to LaVon et al.; Ser. No. 11/713,906 to LaVon et al.; Ser.No. 11/728,127 to LaVon et al.; Ser. No. 61/073,154 to LaVon; and61/073,169 to LaVon; US Pub. Nos. 2004/0162536 to Becker filed on Feb.11, 2004; 2007/0167928 to Becker filed on Mar. 13, 2007; 2007/0179464 toBecker filed on Mar. 13, 2007; 2007/0156108 to Becker filed on Mar. 13,2007; and 2004/0167486 to Busam filed on Feb. 11, 2004; U.S. Ser. Nos.60/936,102 to Hundorf filed on Jun. 18, 2007; 60/936,109 to Hundorffiled on Jun. 18, 2007; 60/936,149 to Hundorf filed on Jun. 18, 2007;60/936,085 to Ashton filed on Jun. 18, 2007; 60/936,084 to Ashton filedon Jun. 18, 2007; 60/936,150 to Ashton filed on Jun. 18, 2007;60/936,146 to Asthon filed on Jun. 18, 2007; 60/936,037 to Ashton filedon Jun. 18, 2007; and 61/091,799 to Hundorf filed on Aug. 26, 2008.

In one alternative embodiment of the present invention a portion of theabsorbent article, such as part or all of the topsheet, part or all ofthe barrier leg cuffs and the like, may be optionally coated with alotion, as is known in the art. Examples of suitable lotions include,but are not limited to, those described in U.S. Pat. No. 5,607,760 toRoe on; U.S. Pat. No. 5,609,587 to Roe; U.S. Pat. No. 5,635,191 to Roeet al.; U.S. Pat. No. 5,643,588 to Roe et al.; and U.S. Pat. No.5,968,025 to Roe et al.

The liquid-activated colorant may be included in the liquid activatedformulation at a level which is within the range of about 0.01 weightpercent to about 20 weight percent, or may be incorporated into theliquid activated formulation at a level which is within the range ofabout 0.02 weight percent to about 15 weight percent, based upon thetotal weight of the liquid activated formulation. The liquid activatedcolorant may be included in the liquid activated formulation at a levelwhich is within the range of about 0.02 weight percent to about 10weight percent, or may be incorporated into the liquid activatedformulation at a level which is within the range of about 0.02 weightpercent to about 2 weight percent.

The hydrochromic ionic compound may be included in the liquid activatedformulation at a level which is within the range of about 0.01 weightpercent to about 35 weight percent, or may be incorporated into theliquid activated formulation at a level which is within the range ofabout 0.1 weight percent to about 30 weight percent, based upon thetotal weight of the liquid activated formulation. The hydrochromic ioniccompound may be included in the liquid activated formulation at a levelwhich is within the range of about 0.1 weight percent to about 25 weightpercent, or may be incorporated into the liquid activated formulation ata level which is within the range of about 0.1 weight percent to about20 weight percent.

The opacifier may be included in the liquid activated formulation at alevel which is within the range of about 0.5 weight percent to about 75weight percent or may be incorporated into the liquid activatedformulation at a level which is within the range of about 10 weightpercent to about 50 weight percent, based upon the total weight of theliquid activated formulation. The opacifier may be included in theliquid activated formulation at a level which is within the range ofabout 20 weight percent to about 45 weight percent, or may beincorporated into the liquid activated formulation at a level which iswithin the range of about 30 weight percent to about 40 weight percent.

In some embodiments, the liquid-activated colorant may be about 0.1weight percent of the liquid-activated formulation, or may be from about0.01 to about 5 weight percent of the liquid-activated formulation. Insome embodiments, the opacifier may be from about 0.5 to about 60 wt %of the liquid-activated formulation. For opacifiers such as or similarto titanium dioxide, the weight percent may be from about 0.5% to about2%. For opacifiers such as or similar to aluminum silicate, the weightpercent may be from about 30% to about 70%. In some embodiments, thehydrochromic ionic compound may be present in the liquid-activatedformulation about 0.1 wt % or from about 0.05 wt % to 0.15 wt % for astrong base like sodium hydroxide or a strong acid like hydrochloricacid. For weaker acids and bases, the hydrochromic ionic compound mayhave a weight percent of about 10% or be in a range of from about 2% toabout 18%. In some embodiments, the binding matrix may be from about 25wt % to about 75 wt % of the liquid-activated formulation.

EXAMPLES

The present invention is illustrated by the following examples, whichare merely for the purpose of illustration and are not to be regarded aslimiting the scope of the invention or the manner in which it can bepracticed. Unless specifically indicated otherwise, parts andpercentages are given by weight. Examples may include any of thecompositions and components disclosed in U.S. Patent Application Ser.No. 61/705,861, titled “Liquid Activated Color Change Ink and Methods ofUse”.

INCI or Trade Name FUNCTION/Supplier Sodium Aluminum Silicate 48.20%Sipernat ™ 820A Opacifier/Evonik Inc. Bromocresol Green (Free Acid)0.30% Colorant/Curtiss Labs Sodium Hydrogen Carbonate 11.00%hydrochromic ionic compound/Sigma-Aldrich Performathox 450 26.00%C20-C40 Pareth-10 Surfactant/New Phase Inc. Microcrystalline Wax 11.00%Multiwax ™W-835 Tackifier/Sonneborn Isononyl Isononylnonoate 1.50%Particle Wetting Agent/Alzo Inc. Polyhydroxystearic Acid 2.00%Dispersun ™ DSP- Particle Wetting OL100 Agent/Innospec Inc. 100.00%EXAMPLE 2 Sodium Aluminum Silicate 34.15% Sipenat ™ 820AOpacifier/Evonik Inc. m-Cresol Purple (Free Acid ) 0.25%Colorant/Sigma-Aldrich Sodium Carbonate 14.00% hydrochromic ioniccompound/Sigma-Aldrich Ethylene Vinyl Acetate 17.60% Elvax ™ 40W BinderBase Material/DuPont Performathox 480 16.00% C20-C40 Pareth-40Surfactant/New Phase Inc. Terpene Phenolic 11.00% Sylvares ™ TP96Tackifier/Arizona Chemical Inc. Titanium Dioxide 3.00% Hombitan ™ ANOpacifier/Sachtleben C12-15 Alkyl Benzoate 2.00% Finsolv TN ™ ParticleWetting Agent/Innospec Inc. Polyhydroxystearic Acid 2.00% Dispersun DSP-Particle Wetting OL100 Agent/Innospec Inc. 100.00% EXAMPLE 3 SodiumAluminum Silicate 31.15% Sipernat 820A Opacifier/Evonik Inc. BromothymolBlue (free acid) 0.25% Colorant/Sigma-Aldrich Sodium Carbonate 14.00%hydrochromic ionic compound/Sigma-Aldrich Ethylene Vinyl Acetate 17.60%Elvax ™ 40W Binder Base Material/DuPont Performathox 480 16.00% C20-C40Pareth-40 Surfactant/New Phase Inc. Terpene Phenolic 11.00% Sylvares ™TP96 Tackifier/Arizona Chemical Inc. Titanium Dioxide 3.00% Hombitan ™AN Opacifier/Sachleben Arquad HTL8-MS 3.00% Stearyl EthylhexyldimmoniumQuaternary Leaching Methosulfate Aid/AkzoNobel Inc. C12-15 AlkylBenzoate 2.00% Finsolv TN ™ Particle Wetting Agent/Innospec Inc.Polyhydroxystearic Acid 2.00% Dispersun ™ DSP-OL100 Particle WettingAgent/Innospec Inc. 100.00% EXAMPLE 4 Sodium Aluminum Silicate 34.90%Sipernat 820A Opacifier/Evonik Inc. Sylvatac ™ RE98 15.00%Pentaerythritol Rosin Ester Tackifier/Arizona Chemical Inc. Poly-Pale ™6.00% Partially Dimerized Rosin Tackifier/Eastman Inc. Performathox 45020.00% C20-C40 Pareth-10 Surfactant/New Phase Inc. Microcrystalline Wax12.00% Microcrystalline Wax Tackifier/Sonneborn Inc. W835 Ethoquad C/252.00% Cocoalkylmethyl(polyoxyethylene(15)) Quaternary Leaching ammoniumchloride Aid/Akzo Nobel Bromocresol Green, free acid 0.20%Colorant/Curtiss Labs Sodium Hydrogen Carbonate 7.00% hydrochromic ioniccompound/Sigma-Aldrich Irganox 1010 0.40%Tetrakis[methlene(3,5-di-(tert)- Anti-Oxidant/Ciba Inc. butyl-4-hydroxyhydrocinnamate)]methane (irganox 1010) Titanium Dioxide 2.50%Hombitan ™ AN Opacifier/Sachleben Inc. 100.00% EXAMPLE 5 Sodium AluminumSilicate 34.40% Sipernat 820A Opacifier/Evonik Inc. Sylvatac ™ RE9818.00% Pentaerythritol Rosin Ester Tackifier/Arizona Chemical Inc.Poly-Pale ™ 7.00% Partially Dimerized Rosin Tackifier/Eastman Inc.Performathox 450 17.00% C20-C40 Pareth-10 Surfactant/New Phase Inc.Microcrystalline Wax 12.00% Microcrystalline Wax Tackifier/SonnebornInc. W835 Ethoquad C/25 2.00% Cocoalkylmethyl(polyoxyethylene(15))Quaternary Leaching ammonium chloride Aid/Akzo Nobel Sodium HydrogenCarbonate 9.00% hydrochromic ionic compound/Sigma-Aldrich Bromocresolpurple, free acid 0.20% Colorant/Sigma-Aldrich Irganox 1010 0.40%Tetrakis[methlene(3,5-di-(tert)- Anti-Oxidant/Ciba Inc. butyl-4-hydroxyhydrocinnamate)]methane (irganox 1010) 100.00%Examples 1-5 may be prepared in the following manner.

Those ingredients that are solids at room temperature are first meltedat a temperature of around 90 C. These ingredients include the bindingagents, hot melt adhesives, waxes, surfactants, and optional ingredientslike the anti-oxidants. Typically, a temperature of around 80 C to 100 Cwould be required to melt these ingredients. After melting to the liquidstate on a hot plate, the materials are well mixed using a propellermixer like an IKA RW-20 (or similar mixer) until the mixture ishomogeneous. While keeping this mixture heated and mixed, the SodiumAluminum Silicate powder is homogeneously mixed into the composition.Next, the hydrochromic ionic compound, sodium hydrogen carbonate, ismixed into the composition while maintaining heating. Finally, thecolorant like bromocresol green (free acid) is well mixed into thecomposition until the mixture is homogeneous. Heat can be maintained onthe composition to make films using a draw-down wire or the compositioncan be cooled down to room temperature for future use.

Examples 6a and 6b

The top formula, example 6a, is made with water and coated onto thepolyethylene film for color change performance observations. Thecomposition right below, example 6b, is the composition's concentrationsafter the water has been removed from the wetness indicator film coatingvia heating with a heated blow dryer:

Joncryl 624 18.40% Water 36.08% Sipernat 820a 22.90% m-cresol 0.04%purple PEG-3000 22.27% NaOH/50% 0.31% Joncryl 624 16.86% Water 0.00%Sipernat 820a 41.96% m-cresol 0.08% purple PEG-3000 40.81% NaOH/50%0.29%

Examples 6a and 6b may be prepared by the following steps:

-   -   1) The Joncryl 624 Acrylic Polymer is weighed out into the        beaker    -   2) Water is weighed out and added. Mix with a spatula until        homogeneous and milky white in appearance    -   3) The Sipernat 820a Powder is added and mixed into the liquid        until a viscous white and homogeneous paste results    -   4) Weigh in the m-cresol purple and mix well    -   5) Liquify the polyethylene glycol 3000 by heating and mix in        well with a spatula    -   6) Add the 50% water solution of Sodium Hydroxide and mix well.        Make a film onto the polyethylene using a bird or wired thin        film application device.        Either allow the water to evaporate overnight slowly or speed up        the evaporation rate of the water by heating with a blow dryer        or other suitable device.

According to an aspect of the invention, FIGS. 1-3 show an absorbentarticle 10 in an unfastened and uncontracted state that has a liquidpermeable topsheet 12, a liquid impermeable backsheet 14, a liquidabsorbent core 16 disposed between the topsheet 12 and the backsheet 14,further comprising a liquid indicator 20. The liquid indicator 20comprises a coating 18 of liquid indicating ink disposed on thebacksheet 14, between the backsheet 14 and the absorbent core 16, suchthat it is visually revealed when the coating 18 is wetted with bodyfluids. The liquid indicator is the liquid-activated formulation asdescribed above. This liquid indicator may change color entirely when incontact with liquid, or may change noticeable shades of color, or maychange from an almost white (so as it appears that there is no colorantthere) to a color, or may change from a color to a white/colorlessstate. FIG. 2 shows an example of how the absorbent article may appearwhen wet, wherein the liquid indicator 20 appears in a raindrop patternthat is visible when wet. The liquid-activated formulation may be asingle layer.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A liquid-activated formulation comprising: (A) aliquid-activated colorant; (B) a hydrochromic ionic compound; (C) anopacifier; and (D) a hot melt binding matrix.
 2. The liquid-activatedformulation of claim 1, wherein the hot melt binding matrix comprises atleast one binding agent selected from the group consisting ofacrylic-based binders, adhesives, hot melt adhesive components, waxesand modified waxes like oxidized waxes, surfactants, rosin esters,rosins and polymerized rosins, modified styrene-acrylic polymers andtheir salts, polyethylene glycols, polymerized rosins, styrenatedterpenes, polyterpene resins, terpene phenolics, quaternary ammoniumcompounds, quaternary polymers, rubbers, latexes and latex emulsions,cationic clay materials, ethoxylated quaternary ammonium compounds,quaternized silicone compounds, cationic guars, cationic exchangeresins, anionic exchange resins, and combinations thereof.
 3. Theliquid-activated formulation of claim 1, wherein the binding matrixcomprises a first binding agent and a second binding agent.
 4. Theliquid-activated formulation of claim 1, wherein the hot melt bindingmatrix is a hot melt adhesive matrix.
 5. The liquid-activatedformulation of claim 1, further comprising one or more selected from thegroup consisting of a stabilizer, a surfactant, a structural adjunct,and combinations thereof.
 6. The liquid-activated formulation of claim5, wherein said stabilizer is selected from the group consisting ofmonostearyl phosphate, citrate esters, alcohol ethoxycarboxylates,glycolate esters, lactate esters, fatty acids, ether carboxylic acids,fatty acid methyl esters, sulfate esters, fruit acids like citric acidand malic acid, inorganic acids like sulfuric acid, monoethanolamine,diethanolamine, triethanolamine, dipropyllenetriamine, diiosopropylamine, 1,3-bis(methylamine)-cyclohexane, 1,3Pentanediamine, sodiumhydroxide, magnesium hydroxide, and combinations thereof.
 7. Theliquid-activated formulation of claim 5, wherein said surfactant isselected from the group consisting of nonionic surfactants, anionicsurfactants, cationic surfactants, amphoteric surfactants, andcombinations thereof.
 8. The liquid-activated formulation of claim 5,wherein said structural adjunct is selected from the group consisting ofHLB modifiers, viscosity modifiers, hardening agents, anti-leachingaids, anti-oxidants, wetting agents, solvents, and combinations thereof.9. The liquid-activated formulation of claim 5, further comprising apermanent colorant.
 10. An absorbent article comprising theliquid-activated formulation of claim 1, wherein said liquid-activatedformulation is affixed to a structural component of the absorbentarticle.
 11. An absorbent article comprising the liquid-activatedformulation of claim 1, wherein the article comprises a backsheet, atopsheet, an absorbent core disposed between the backsheet and thetopsheet, wherein the liquid-activated formulation is a single layer anddisposed between the backsheet and the absorbent core.
 12. An absorbentarticle comprising the liquid-activated formulation of claim 1, whereinthe article comprises a backsheet, a topsheet, an absorbent coredisposed between the backsheet and the topsheet, wherein theliquid-activated formulation is a single layer and disposed between thetopsheet and the absorbent core.
 13. The liquid-activated inkformulation of claim 1, wherein the hot melt binding matrix has a meltpoint of at least about 50° C.
 14. The liquid-activated formulation ofclaim 2, wherein a binding agent has a cationic charge or multiplecationic charges.
 15. The liquid-activated formulation of claim 2,wherein a binding agent has an anionic charge or multiple anioniccharges.
 16. The liquid-activated formulation of claim 2, wherein abinding agent has an anionic charge and a cationic charge or amultiplicity of cationic and anionic charges.
 17. The liquid-activatedformulation of claim 1, wherein the binding matrix hinders leaching ofthe colorant.
 18. The liquid activated formulation as specified in claim1 wherein the liquid activated colorant is selected from the groupconsisting of Malachite green, brilliant green, crystal violet,erythrosine B, methyl green, methyl violet 2D, picric acid, naphtholyellow S, quinaldine red, eosine Y, metanil yellow, m-cresol purple,thymol blue, xylenol blue, basis fuchsin, eosin B,4-p-aminophenol(azo)benzenesulphonic acid-sodium salt, cresol red,martius yellow, phloxine B, methyl yellow, bromophenol blue, congo red,methyl orange, bromochlorophenol blue (water soluble or free acid form),ethyl orange, fluorocene WS, bromocresol green, chrysoidine, methyl redsodium salt, alizarine red S—H2O, cochineal, chlorophenol red,bromocresol purple, 4-naphtha, alizarin, nitrazine yellow, bromothymolblue, brilliant yellow, neutral red, rosalic acid, phenol red, 3-nitrophenol, orange II, phenolphthalein, o-cresolphthalein, nile blue A,thymolphthalein, aniline blue WS, alizarine yellow GG, mordant orange,tropaolin O, orange G, acid fuchsin, thiazol yellow G, indigo carmine,FD&C Blue No. 1, FD&C Blue No. 2, FD&C Green No. 3, FD&C Red No. 40,FD&C Red No. 4, FD&C Yellow No. 5, FD&C Yellow No. 6, C.I. Food Blue 5,and C.I. Food Red 7, D&C Yellow No. 10, D&C Yellow No. 7, D&C Yellow No.2, D&C Yellow No. 8, D&C Orange No. 4, D&C Red No. 22, D&C Red No. 28,D&C Red No. 33, D&C Green No. 8, D&C Green No. 5, D&C Brown No. 1,bromopyrogallol red, bromoxylenol blue, methylene blue, monoazo dyessuch as acid alizarin voliet N, monoazo pyrazoline dyes, diazo dyes,anthraquinone dyes, amphoteric anthraquinone dyes, triphenylmethanedyes, phthalein type dyes, xanthene dyes, heterocyclic acridinearomatics, diphenylmethane dyes, triphenylmethane dyes, cationicthiazine dyes, cationic anthraquinone dyes such as basic blue 47,phthalocyanine type dyes, anthraquinone type, neutral complex dyes,terpene type dyes, and any combination thereof.
 19. The liquid activatedformulation as specified in claim 1 wherein the hydrochromic ioniccompound is selected from the group consisting of lithium hydrogensulfate, lithium hydrogen carbonate, potassium hydrogen sulfate,potassium hydrogen carbonate, rubidium hydrogen sulfate, rubidiumhydrogen carbonate, cesium hydrogen sulfate, cesium hydrogen carbonate,sodium hydrogen sulfate, sodium hydrogen carbonate, sodium carbonate,cesium hydroxide, lithium hydroxide, potassium hydroxide, calciumhydroxide, magnesium hydroxide, sodium thiosulfate penta hydrate, sodiumhydroxide, rubidium hydroxide, cobalt chloride, cobalt nitrate, coppersulphate copper nitrate, iron (II) sulfate, iron (III) sulfate, iron(II)chloride, iron (III) chloride, sodium aluminum silicate, citricacid, monosodium dihydrogen citrate, disodium hydrogen citrate,trisodium citrate, gluconic acid, sodium gluconate, glycolic acid,sodium glycolate, malic acid, sodium malate, maleic acid, sodiummaleate, acetic acid, phosphoric acid, trisodium phosphate, sodiumdihydrogen phosphate, disodium hydrogen phosphate, monostearylphosphate, monocetyl phosphate, monostearyl citrate, hydrochloric acid,nitric acid, sulfuric acid and combinations thereof.
 20. The liquidactivated formulation as specified in claim 1 wherein the opacifier isselected from the group consisting of titanium dioxide, calciumcarbonate, calcium hydroxide, sodium silicate, potassium silicate,silica, starch, ethocell, methocell, barium carbonate, barium silicate,calcium silicate, aluminum silicate, aluminum hydroxide, aluminum oxide,sodium aluminum silicate, zirconium silicate, magnesium aluminumsilicate, and styrene/acrylate copolymers.
 21. The liquid activatedformulation as specified in claim 1 wherein the a liquid activatedcolorant is present in the liquid activated formulation in an amountwhich is within the range of about 0.01 weight percent to about 20weight percent, wherein the hydrochromic ionic compound is present inthe liquid activated formulation in an amount which is within the rangeof about 0.05 weight percent to about 35 weight percent, wherein theopacifier is present in the liquid activated formulation in an amountwhich is within the range of about 5 weight percent to about 75 weightpercent, and wherein the binding matrix is present in the liquidactivated formulation in an amount which is within the range of about 5weight percent to about 75 weight percent, based upon the total weightof the liquid activated formulation.
 22. The liquid-activatedformulation of claim 1, wherein the liquid-activated formulation has acolor transition selected from the group consisting of a) colored touncolored, b) uncolored to colored, c) colored to a different color, ord) a combination of a) and b) and c).